Reaction product of a dialdehyde polysaccharide with a metal salt and preparing paper containing same



United States Patent 3,236,721 REACTKON PRODUCT OF A DIALDEHYDE POLY.

SACCHARIDE WITH A METAL SALT AND PRE- PARHNG PAPER CONTAINING SAME James Huey Curtis, Elirhart, llnd., assignor to Miles Laboratories, lino, Ellrhart, Iud., a corporation of lndiana No Drawing. Filed June 11, 1964, Ser. No. 374,293 9 Claims. ((11. 162-175) This application is a continuation-in-part of my copending application, Serial No. 267,784, filed March 25, 1963, now abandoned.

This invention relates to the improvement of physical properties of cellulosic materials. More particularly, it relates to a cationized dispersion of a dialdehyde polysaccharide, to a process of producing such cationized dispersion, to a process of using such cationized dispersion to treat cellulosic materials, and to the product obtained from such treated cellulosic materials.

It has been known for some time that cellulosic fibers dispersed in water have a negative surface potential and are therefore not substantive to various negatively charged materials which could otherwise be used to impart desired properties to the cellulosic fibers. For example, the polymeric aldehydes produced by the periodate oxidation of polysaccharides, referred to hereinafter as dialdehyde polysaccharides, are known to contribute strength characteristics to cellulosic fibers when utilized as additives to the wet end of the paper making process. However, the addition of anionic or negatively charged dialdehyde polysaccharides to the negatively charged cellulosic fibers has posed certain problems which it has been possible to solve only by resorting to involved and time consuming operations in which the cellulosic fibers have been pretreated with chemical agents which reverse the charge of the cellulosic surface prior to the addition of a dialdehyde polysaccharide to the cellulosic fibers.

For instance, the aqueous fiber slurries have been contacted with such strongly cationic or positively charged water-soluble materials as large amounts of alum, aqueous dispersions of cationic starches, polymeric amides, and other suitable cationic substances. This procedure is sometimes referred to as fiber pretreatment and the materials used for this purpose known as retention aids or coupling agents. Once the cellulosic fibers have been so treated, anionic dispersions of dialdehyde polysaccharides can be added to the pretreated fibers and retained by means of electrostatic attraction. Such procedures are described in B. T. Hofreiter, G. E. Hamerstrand, C. L. Mehltretter, W. E. Schulz-e, and A. J. Ernst, TAPPI, 43, 639 (1960), G. E. Hamerstrand, B. T. Hofreiter, C. L. Mehltretter, W. E. Schulze, and D. J. Kay, TAPPI, 44, 430 (1961), and in B. T. Hofreiter, G. E. Hamerstrand, D. J. Kay, and C. E. Rist, TAPPI, 45, 177 (1962).

Most such processes utilize a dispersion of a dialdehyde polysaccharide in the presence of an inorganic bisulfite salt to render the dialdehyde polysaccharide strongly anionic.

Thus, in the prior art processes it is necessary to (1) add a suitable retention aid or coupling agent to the cellulosic fibers, and (2) thereafter add to the pretreated cellulosic fibers an anionic dialdehyde polysaccharide dispersion. In practice the process is carried out at various "ice points in the manufacture of cellulosic web materials. For instance, addition has been suggested at the beater, the headbox, the fan pump, and various other points at the wet end of the manufacturing process.

Certain decided disadvantages to the aforementioned methods for the treatment of cellulosic fibers have been encountered. One of these disadvantages is the uneconomical requirement for the use of relatively large amounts of retention aid or coupling agent. It is believed that the use of substantial proportions of such cationic materials results in surface areas of the fibers, which would otherwise be available as potential reaction sites for interaction between the cellulose and the aldehyde groups of the dialdehyde polysaccharide, being occupied by these materials. This may be visualized as a situation wherein the strength-imparting material has fewer contact points available at the fibers surfaces than are needed for full strength development.

Another disadvantage to the use of the aforementioned methods for imparting high wet strength to paper and other cellulosic materials lies in the problems inherent in the use of an inorganic bisulfite salt. It has been found that the use of bisulfite salts in the preparation of dialdehyde polysaccharide dispersions limits the concentration of dialdehyde polysaccharide in these dispersions to a maximum 'of about 3 percent by weight. The reason for this is that at higher concentrations highly viscous thixotropic gels are formed during the cooking procedures. These gels have considerable resistance to break-down into fragments of lower molecular weight, which breakdown is necessary for their successful use. Furthermore, no consistent heat transfer is possible after reaching the peak gel stage.

It is, accordingly, a principal object of this invention to provide cellulosic materials which are characterized by having excellent strength characteristics, particularly with respect to wet strength.

Another object of this invention is to provide a process for improving the properties of cellulosic fibers which is more economical and more effective than the aforementioned prior art processes.

A further object of this invention is to provide such a process which is characterized by practical convenience coupled with the attainment of optimum results.

Yet another object of this invention is to provide a process for the preparation of cellulosic web materials, which process may be readily adapted to conventional techniques utilized in the manufacture of such materials.

Other objects and advantages 'of this invention will be apparent to those skilled in the art from the following detailed disclosure and description.

It has now been found that the disadvantages inherent in previously avail-able processes for the provision of cellulosic materials having improved strength characteristics can be overcome by means of a simple and convenient technique for the treatment of cellulosic fibers. The process generally comprises reaction between a dialdehyde polysaccharide and certain cationizing metal salts under conditions such that there results a product which is cationic in nature and definitely substantive to anionic cellulose. This process results in full availability of the cellulosic fibers to adherence by the cationized dialdehyde polysaccharide. Other advantages yet accrue from the operation of this process. These additional advantages will be further disclosed below.

For the operation of the process of this invention a dialdehyde polysaccharide is first dispersed in water to form an aqueous dispersion of the dialdehyde polysaccharide. Dispersion is accomplished by heating the dialdehyde polysaccharide in water to a temperature of about from 60 C.90 C. while vigorously stirring the mixture.

The concentration of the dialdehyde polysaccharide in the aqueous dispersion may be about from 1 percent to 30 percent by weight, preferably about from 3 percent to 10 percent. Cooking the dialdehyde polysaccharide in water functions to rupture the granules of the dialdehyde polysaccharide. The cook is generally considered to be complete when no unruptured granules are found to be present. This can be ascertained by means of centrifugation or by other appropriate analytical means. Sometimes the dispersion of the dialdehyde polysaccharide can be facilitated by the use of a small amount of a buffer salt such as sodium acetate, sodium citrate, monosodium phosphate, borax or sodium hexametaphosphate. The use of such salts is particularly desirable where dispersions of relatively high concentrations, for example, of above about 10 percent are required. In general, the amount of buffer salt used should be in the range of about from 0.1 percent to 5 percent, preferably about from 0.5 percent to 2.5 percent of the weight of dialdehyde polysaccharide used. Both the temperature of dispersion and the necessity for use of a salt are to a large extent dependent upon the composition of the water used for preparing the dispersion. For instance, water having a relatively high total alkalinity, for example, 200 p.p.m. or higher, requires a cooking temperature, for a 3 percent to 5 percent by weight dispersion, in the range of about from 60 C.70 C. Water of lower total alkalinity, for example, about 100 ppm. or below, may require a cooking temperature of upwards of about 80 C., for instance, temperatures in the range of about from 80 C.95 C. It should be noted that the use of low temperatures is possible where water of high alkalinity is used or where basic reacting buffer salts are added. The total alkalinity may be defined as ten times the number of milliliters of 0.02 N sulfuric acid required .to reduce the pH of a 100 milliliter water sample to pH 4.0. This test is recorded as TAPPI Standard T 620 m-55, Sheet 4.

Following the step of dispersing the dialdehyde polysaccharide in water, the pH of the resulting dispersion is lowered to one in the range of about from pH 2.0 to pH 5.0 and preferably about pH 3.5. The lowering of the pH of the dialdehyde polysaccharide dispersion may be conveniently accomplished by adding any dilute acid such as hydrochloric acid, sulfuric acid or formic acid. Sulfuric acid is generally preferred for this purpose. This pH adjustment prevents alkaline material which may be present in the water used for preparing the dispersion from further degrading the dialdehyde polysaccharide. Such degradation results in undesirably low wet strength being attained from use of such dispersions, especially where the dispersions are subjected to long periods of heating. This pH adjustment also exerts beneficial effects in the later processing steps serving to both catalyze the reaction between the dialdehyde polysaccharide and the cationizing salt and to prevent agglomeration upon interaction between these materials.

Following adjustment of the pH of the aqueous dialdehyde polysaccharide dispersion the cationizing salt to be used is added to the dialdehyde polysaccharide dispersion at the cooking temperature thereof or after the dispersion has been allowed to cool slightly, for example, to a temperature in the range of about from 25 C. to 75 C. The cationizing salt is then allowed to react with the dialdehyde polysaccharide in dispersion for a period, generally, of about from 1 minute to minutes in length. The resulting dispersion of cationized dialdehyde polysaccharide is of colloidal nature and can then be utilized in application to cellulosic fibers such as by adding said cationized dialdehyde polysaccharide to an aqueous suspension of cellulosic fibers such as found in the beater of a paper machine during the process of paper manufacture. Likewise, the addition can be at various other points in the paper making process or corresponding points in the processing of other cellulosic fibers. Wet strength increases in the range of about from percent to 1000 percent over untreated fibers have been realized using this process, depending on the type of fiber and the amount of cationized dialdehyde polysaccharide added.

The suggested pH range of pH 2.05.0, and preferably pH 3.5, is an optimum one for facilitating the interaction between the dispersed dialdehyde polysaccharide and the cationizing sa-lt. Further, the cationized dialdehyde polysaccharide formed at this pH is a hydrophilic colloid which, in dilute dispersions, for example in concentrations of about from 1 percent to 3 percent by weight, has shown excellent stability upon prolonged storage with no flocculation or formation of agglomerates. If the pH of the dialdehyde polysaccharide-cationizing salt reaction system is above about pH 7.0, degradation of the dialdehyde polysaccharide takes place. With some of the cationizing agents, such as the tin salts for example, flocculation of the dispersed dialdehyde polysaccharide will take place at a pH above about pH 5.0. The use of such dispersions containing degraded or flocculated material results in very little, if any, wet strength improvement.

The amount of cationizing salt added to the dispersion of the dialdehyde polysaccharide depends in part upon its chemical nature. Economic considerations are also involved. Optimum results vary with each type used. The general range, however, is about from 2.5 percent to 100 percent by weight of the dialdehyde polysaccharide, and preferably about from 5 percent to 50 percent.

The cationized dialdehyde polysaccharide dispersion prepared as above described has been found to be highly substantive to cellulosic fibers such that the addition of any retention aid, such as a cationic starch or alum, is unnecessary where these dispersions are used. It is believed that the attractive forces between the electropositively charged macromolecules of cationized dialdehyde polysaccharide and the electronegatively charged fiber surfaces are of a sufficient magnitude to cause satisfactory adherence of the cationized dialdehyde polysaccharide to the fibers and to obviate the necessity for the use of any other substance.

The dialdehyde polysaccharides utilized in the process of this invention comprise a series of materials which are known to be capable of cross-linking cellulose. These materials may be generally described as polymeric dialdehydes, a preferred embodiment of which is dialdehyde starch. They are frequently referred to as periodate oxidized polysaccharides because of their preparation by the well known oxidation of polysaccharides with periodic acid. This preparation may be illustrated by the conversion of starch to dialdehyde starch or periodate oxidized starch using periodic acid in accordance with the followmg equation:

CHzOH wherein n stands for the number of repeating structural units in the molecule, which may range from as few as about 20 to as many as several thousands. The preparation of dialdehyde starch is more particularly described in U.S. Patent No. 2,713,553, to Charles L. Mehltretter.

The dialdehyde polysaccharide to be used in the process of this invention may be the dialdehyde derivative of any polysaccharide such as corn, wheat, rice, tapioca or potato starches, amyloses, amylopectins, celluloses, gums, dextrans, algins, insulins and others. Of these polysaccharides, the dialdehyde derivatives of starch known generically as dialdehyde starch are the best known and most widely used. However, where it is desired to have derivatives of other polysaccharides, these may be used as well.

In general, it is preferred to use dialdehyde polysaccharides which are about from 90 percent to 100 percent oxidized, that is those wherein 90 to 100 of each 100 of the original anhydroglucose units have been converted to dialdehyde units such as by periodate oxidation as above described.

The novel cationizing agents of this invention may be characterized as water-soluble acidic salts of titanium, zinc, strontium, tin, chromium, and zirconium. Especially preferred are salts of zirconium such as zirconium oxychloride, ZrOCl zirconium chloride, ZrCl and zirconium sulfate, Zr(SO -4H O. These salts, all of them acid-reacting in aqueous solution, are believed to react with the dialdehyde polysaccharide to produce a metal derivative of the dialdehyde polysaccharide such as a metal complex.

Because of the acidic nature of the salts used as cationizing agents, it is frequently unnecessary to adjust the pH of the dialdehyde polysaccharide dispersion previous to the addition of the catonizing salt. In fact the optimum pH range for conducting the reaction between the dispersed dialdeyhde polysaccharide and the metal salt is one in the range of about from pH 2.0 to pH 5.0. The pH of the dialdehyde polysaccharide dispersion following the addition of the cationizing salt is generally found to be at approximately this range. If desired, however, the dialdehyde polysaccharide dispersion may be adjusted to one in the suggested pH range and the cationizing salt added to the pH-adjusted dispersion as described above.

The cationized dialdehyde polysaccharide dispersions prepared as above described can be added to any desired cellulosic material. More particularly, these dispersions can be added to a wide variety of cellulosic fibers or mixtures thereof. For example, any of the following as well as others can be successfully employed: unbleached kraft pulp, semi-bleached kraft pulp, bleached kraft pulp, unbleached sulfite pulp, semibleached sulfite pulp, bleached sulfite pulp, unbleached semi-chemical pulp, semi-bleached semi-chemical pulp, bleached semi-chemical pulp, unbleached soda pulp, semi-bleached soda pulp, bleached soda pulp, unbleached and cooked cotton rag stock, cooked bagasse fibers, either acid or alkali cooked cotton linter pulp of various types and grades, mechanical pulp from both coniferous and deciduous woods, cooked and semi-cooked hemp, sisal, ramie, jute, caroa and other bast fibers such as bamboo, palm and many grasses, old paper stock made up of any or all of any mixture of used papermaking fibers, cooked straw fibers, cooked flax fibers, and, in fact, any fibrous cellulosic material that lends itself to the formation of water laid cellulosic webs or forms fabrics from any aqueous suspension of its fibers.

As pointed out above, the cationized dialdehyde polysaccharide dispersion can be incorporated into various points in cellulose processing. For example, in the paper making process it can be incorporated into the pulp slurry at any point at the wet end of the paper machine. Alternatively, it can be applied from a tub size or at a size press or from showers to the dried or partially dried sheet.

These cationized dispersions can be added to cellulose slurries in amounts of about from 0.05 percent to 10 percent and preferably from 0.1 percent to 5 percent based on the weight of oven dry pulp, said percentage based on the weight of dialdehyde polysaccharide employed in the formation of the cationized dialdehyde polysaccharide dispersion.

In addition to the advantages pointed out heretofore, a primary advantage of this invention is the use of a stable cationized dialdehyde polysaccharide dispersion which, as pointed out above, obviates the necessity for using any other material as a retention aid for the dialdehyde polysaccharide. For example, the use of cationic starches or large amounts of alum as required in the prior art is no longer necessary. In particular, the use of the dispersions of the reaction product of a dialdehyde polysaccharide with the particular metal salts of this invention is preferable to the use of alum for the following reasons:

(1) Amounts of salts required are minute, compared to large amounts of alum (11 percent based on pulp weight) required by prior art processes.

(2) These salts do not interfere with, or deleteriously affect other properties of the fibrous web or final product.

(3) Degradation, weakening and stiffening by alum are entirely avoided, thus maintaining desirable strength softness and absorbency characteristics of fibrous product.

This invention will be better understood by reference to the following detailed examples which, however, are not to be considered as unduly limiting the scope of the instant invention, which is defined in the claims appended hereto.

Example 1 Procedure for preparation of cationized dialdehyde starch.100 g. of dialdehyde starch as received, 100 percent oxidized, 11.7 percent moisture, were added to 1 liter of 100 ppm. total alkalinity Water and agitated until well mixed. The mixture was heated to 92 C. and allowed to cook at 90 C.92 C. for 32 minutes. The dispersion was cooled to C. and 20 percent solid zirconium chloride based on the weight of the dialdehyde starch was added. After the addition of the zirconium chloride, the color of the dispersion became slightly amher. The final pH was 2.7.

Sheet-making proeedure.Bleached kraft pulp was beaten to 425 cc. Canadian Standard Freeness and slurried in water to a consistency of 1 percent. The pH of the slurry was adjusted to pH 4.55 .5 with dilute sulfuric acid. The required amount of pulp slurry to make 20 sheets was then withdrawn and treated with the cationized dialdehyde starch. After mixing thoroughly 250 ml. portions of the treated slurry were measured out for each 2.5 g. sheet and added to the pre-filled Deckle box of a Noble and Wood sheet machine. Water used to fill the Deckle box was adjusted to pH 4.55.5. Pulp consistency in the Deckle box was approximately 0.05 percent. After forming the sheet using a white water return system, the wet sheet was pressed with the felt press of the Noble and Wood machine to a consistency of approximately 32 percent. The sheet, still on the wire, was then dried at 220 F. during a three-minute drying cycle on the steam heated dryer of the sheet machine.

The blanks, in which no cationized dialdehyde starch was added were formed in the same manner.

Sheets containing zirconium chloride but no dialdehyde starch were formed in the same manner by simply adding the desired amount of ZrCl to the pulp slurry.

Procedure for testing of hand-sheets.-The formed and dried hand-sheets were tested for dry tensile strength and wet tensile strength using one-half inch strips over a fourinch span of the tensile tester both without curing and with curing at 230 F. for 10 minutes according to TAPPI Standards methods.

The data obtained are shown in Table l. The percentages given are by weight unless otherwise noted.

Example 5 The procedure of Example 1 'was carried out using dialdehyde starch cation-ized with zirconium chloride with bleached krapt of 45 cc. c.s.f. In all instances the amount of zirconinum chloride used was 20 percent based on dialdehyde starch. The amount of cationized dialdehyde starch used based on oven dry pulp was:

Sheet desig- Percent nation The data obtained are shown in Table 5.

TABLE [Part A] OFF MACHINE Sheet designation 47 48 49 50 51 Wet tensile strength, lb./in.:

5, 590 4, 990 4, 360 180 2, 650 Dry tensile strength, lbJin. 33. 6 34. 7 36. 7 43.0 Dry breaking length, rn 9, 320 9, 530 10, 070 10, 320 1,1790 Wet bursting strength 2 (5 min. soaking) 4. 2 30.0 55. 7 77. 8 107. 9 Dry bursting strength 145 157 159 163 172 Internal tearing resistance 3 1 Soaking time in minutes in distilled H O.

Reading 2 Expressed as percent Mullen, b

TABLE 5 [Part 13] CURED 1 Sheet designation 47 48 49 50 51 Wet tensile strength, lb./in.:

5,980 5, 250 4, 720 18 ,810 Dry tensile strength, lb./in 34. 1 33.7 35. 4 46. 8 39. 2 Dry breaking length, m 9,350 9, 240 9, 720 12, 840 10, 750 Wet bursting strength 3 (5 min. soaking) 5. 7 35. 3 60. 1 114. 4 125. 1 Dry bursting strength 142 155 165 170 167 Apparent density, g./cc 0.508 0.524 0.510 0.521 0.513 Bulk, cc./g 1. 97 1. 91 1.96 1. 92 1. 95

1 Cured in oven for minutes at 105 C. 2 Soaking time in minutes in distilled H2O.

Beading 3 Expressed as percent Mullem l00percent Mullen. The following example shows results obtained with additional cationizing salts which are effective in producing strength increases in accordance With this invention.

Example 6 The procedures of Example 1 were carried out using various suitable cationizing agents. A bleached kraft pulp having a Canadian Standard Freeness of 450 cc. was used in the formation of the paper sheets. The cationizing salts were all used in amounts of weight percent based on weight of dialdehyde starch. The ream weight of TABLE 0 Sheet designation Cationizing salt Wet tensile,

Wet breaking lb./in. width length, m.

,.. aw s m (3000330001 gnaw-en Ti(S04)z In summary, this invention provides a process for producing a novel cationized dialdehyde polysaccharide dispersion which utilizes as cationizing agent a water-solub1e acidic salt of titanium, zinc, strontium, tin, chromium, or zirconium. These novel dispersions when added to cellulosic materials provide a product having enhanced wet and dry strengths previously unobtainable.

What is claimed is:

1. A process for improving the physical properties of cellulosic materials which comprises reacting an aqueous dispersion of a dialdehyde polysacoharide with about 2.5 to about 100 weight percent, based on the weight of the dialdehyde polysaccharide, of a water-soluble acidic salt of a metal selected from the group consisting of titanium, zinc, strontium, tin, chromium and zirconium at a pH less than about 7.0 and at a temperature in the range of about from 25 C. to 95 C. to form a cationized dialdehyde polysaccharide dispersion, then adding said cationized dialdehyde polysaccharide dispersion to cellulosic fibers in an amount, based on oven dry fibers, of about 0.05 to about 10 weight percent dialdehyde polysaccharide employed in the formation of the cationized dialdehyde polysaccharide dispersion, and thereafter removing excess water from the treated cellulosic fibers.

2. A process according to claim 1 wherein the metal salt is zirconium oxychloride.

3. A process according to claim 1 wherein the dialdehyde polysaccharide is dialdehyde starch.

4. A process for improving the physical properties of cellulosic materials which comprises reacting an aqueous dispersion of a dialdehyde polysaccharide with about 5 to about weight percent, based on the weight of the dialdehyde polysaccharide, of a water-soluble acidic salt of a metal selected from the group consisting of titanium, zinc, strontium, tin, chromium and zirconium at a pH of about 2.0 to about 5.0 and at a temperature in the range of about from 25 C. to 95 C. to form a cationized dialdehyde polysaccharide dispersion, then adding said cationized dialdehyde polysaccharide dispersion to an aqueous slurry of cellulosic fibers in an amount, based on oven dry pulp, of about 0.1 to about 5 weight percent dialdehyde polysaccharide employed in the formation of the cationized dialdehyde polysaccharide dispersion, and thereafter removing excess water from the treated cellulosic fibers.

5. A process according to claim 4 wherein the metal salt is zirconium oxychloride.

6. A process for producing a dispersion of a reaction product of a dialdehyde polysaccharide with a metal salt which comprises heating a mixture of a dialdehyde polysaccharide with water wherein said mixture contains about 1 to about 30 weight percent dialdehyde polysaccharide at a temperature of about C. to about C. for a period of time sufficient to insure that no unruptured granules of dialdehyde polysaccharide remain in the resulting dispersion, adding to the dispersion at a pH less than about 7.0 a water-soluble acidic salt of a metal selected from the group consisting of titanium, zinc, strontium, tin, chromium and zirconium in an amount of about 2.5 to about weight percent based on the weight of dialdehyde polysaccharide and allowing the added metal salt to 1 1 react with the dialdehyde polysaccharide dispersion at a temperature in the range of about from 25 C. to 95 C.

7. As a composition of matter the reaction product of a dialdehy-de polysaccharide with about 2.5 to about 100 weight percent, based on weight of the dialdehyde polysaccharide, of a water-soluble acidic salt of a metal selected from the group consisting of titanium, zinc, strontium, tin, chromium and zirconium.

8. A process for producing a dispersion of a reaction product of a dialdehyde polysaccharide with a metal salt which comprises heating a mixture of a dialdehyde polysaccharide with water wherein said mixture contains about 3 to about 10 weight percent dialdehyde polysaccharide at a temperature of about 60 C. to about 95 C. for a period of time sufiicient to insure that no unruptured granules of dialdehyde polysaccharide remain in the resulting dispersion, adding to the dispersion at a pH of about 2.0 to about 5.0 a water-soluble acidic salt of a metal selected from the group consisting of titanium, zinc, strontium, tin, chromium and zirconium in an amount of about 5 to about 50 weight percent based on the weight of dialdehyde polysaccharide and allowing the added metal salt to react selected from the group consisting of titanium, zinc,

strontium, tin, chromium and zirconium.

References Cited by the Examiner UNITED STATES PATENTS 3,062,703 11/1962 Hofreiter et a1. 162175 3,117,892 1/1964 Patel et al 260233.3 X

OTHER REFERENCES Mehltretter et al., Preparation of Cationic Dialdehyde Starches for Wet Strength Paper, TAPPI, vol. 45, No. 9, September 1962, pages 750752.

20 DONALL H. SYLVESTER, Primary Examiner. 

1. A PROCESS FOR IMPROVING THE PHYSICAL PROPERTIES OF CELLULOSIC MATERIALS WHICH COMPRISES REACTING AN AQUEOUS DISPERSION OF ADIALDEHYDE POLYSACCHARIDE WITH ABOUT 2.5 TO ABOUT 100 WEIGHT PERCENT, BASED ON THE WEIGHT OF THE DIALDEHYDE POLYSACCHARIDE, OF A WATER-SOLUBLE ACIDIC SALT OF A METAL SELECTED FROM THE GROUP CONSISTING OF TITANIUM, ZINC, STRONTIUM, TIN, CHROMIUM AND ZIRCONIUM AT A PH LESS THAN ABOUT 7.0 AND AT A TEMPERATURE IN THE RANGE OF ABOUT FROM 25*C. TO 95*C. TO FORM A CATIONIZED DIALDEHYDE POLYSACCHARIDE DISPERSION, THEN ADDING SAID CATIONIZED DIALDEHYDE POLYSACCHARIDE DISPERSION TO CELLULOSIC FIBERS IN AN AMOUNT, BASED ON OVEN DRY FIBERS, OF ABOUT 0.05 TO ABOUT 10 WEIGHT PERCENT DIALDEHYDE POLYSACCHARIDE EMPLOYED IN THE FORMATION OF THE CATIONIZED DIALDEHYDE POLYSACCHARIDE DISPERSION, AND THEREAFTER REMOVING EXCESS WATER FROM THE TREATED CELLULOSIC FIBERS.
 7. AS A COMPOSITION OF MATTER THE REACTION PRODUCT OF A DIALDEHYDE POLYSACCHARIDE WITH ABOUT 2.5 TO ABOUT 100 WEIGHT PERCENT, BASED ON WEIGHT OF THE DIALDEHYDE POLYSACCHARIDE, OF A WATER-SOLUBLE ACIDIC SALT OF A METAL SELECTED FROM THE GROUP CONSISTING OF TITANIUM, ZINC, STRONTIUM, TIN, CHROMIUM AND ZIRCONIUM. 